Math Formulas. The arrangement of the binomial coefficients in a pattern of triangle. Probability

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1 Pascual s Triangle: The arrangement of the binomial coefficients in a pattern of triangle. Example of Pascal s Triangle Probability Definition of Probability Probability is a numerical measure of the likelihood of occurrence of an event. The value of probability lies between 0 and 1. If all outcomes of an experiment are equally likely, then the probability is given by, Probability of an event =. Examples of Probability The probability to pick a blue marble from a basket containing 10 blue marbles is 1. Suppose you toss a fair coin. Then the probability of tossing a head or tail is Ratio Definition of Ratio A ratio is a comparison of two numbers by division. Examples of Ratio 4 : 7, 1 : 6, 10 : 3 etc. are examples of ratio. Any ratio a : b can also be written as a to b or.

2 Average Let a 1,a 2,a 3,...,a n be a set of numbers, average = (a 1 + a 2 + a 3,+...+ a n )/n Percent Percent to fraction: x% = x/100 Percentage formula: Rate/100 = Percentage/base Rate: The percent. Base: The amount you are taking the percent of. Percentage: The answer obtained by multiplying the base by the rate Consumer math formulas: Discount = list price discount rate Sale price = list price discount Discount rate = discount list price Sales tax = price of item tax rate Interest = principal rate of interest time Tips = cost of meals tip rate Commission = cost of service commission rate

3 Order of Operations Order of operations refers to the precedence of performing one arithmetical operation over another while working on a mathematical expression. Here are the rules: 1. Evaluate expressions inside parentheses. 2. Evaluate all powers. 3. Perform all multiplications and/or divisions from left to right. 4. Perform all additions and/or subtractions from left to right. Order of operations if not rigidly followed can lead to two different solutions to the same expression. PEMDAS or BEDMAS help you remember order of operations. PEMDAS - Please Excuse My Dear Aunt Sally P - Parentheses E - Exponents M - Multiplication D - Division A - Addition S Subtraction BEDMAS B - Brackets E - Exponents D - Division M - Multiplication A - Addition S - Subtraction Convert Decimals to Fractions (Multiply top and bottom by 10 until you get a whole number, then simplify) To convert a Decimal to a Fraction follow these steps: Step 1: Write down the decimal divided by 1, like this: decimal / 1 Step 2: Multiply both top and bottom by 10 for every number after the decimal point. (For example, if there are two numbers after the decimal point, then use 100, if there are three then use 1000, etc.) Step 3: Simplify (or reduce) the fraction

4 Rules of Fractions Fractions formulas: Converting a mixed number to an improper fraction: Converting an improper fraction to a mixed number: Formula for a proportion: In a proportion, the product of the extremes (ad) equal the product of the means(bc), Thus, ad = bc

5 Geometry formulas: Perimeter: Perimeter of a square: s:length of one side s + s + s + s Perimeter of a rectangle: l: length w: width l + w + l + w Perimeter of a triangle: a + b + c a, b, and c: lengths of the 3 sides Area: Area of a square: s s s: length of one side Area of a rectangle: l: length w: width l w Area of a triangle: (b h)/2 b: length of base h: length of height Area of a trapezoid: (b 1 + b 2 ) h/2 b 1 and b 2 : parallel sides or the bases h: length of height

6 Volume: Volume of a cube: s s s s: length of one side Volume of a box: l w h l: length w: width h: height Volume of a sphere: (4/3) pi r 3 pi: 3.14 r: radius of sphere Volume of a triangular prism: area of triangle Height = (1/2 base height) Height base: length of the base of the triangle height: height of the triangle Height: height of the triangular prism Volume of a cylinder: pi r 2 Height pi: 3.14 r: radius of the circle of the base Height: height of the cylinder

7 Here, we provide you with common geometry formulas for some basic shapes Rectangle: Perimeter = l + l + w + w = 2 l + 2 w Area = l w Square: Perimeter = s + s + s + s = 4 s Area = s 2 Parallelogram: Perimeter = a + a + b + b = 2 a + 2 b Area = b h

8 Rhombus: Perimeter = b + b + b + b = 4 b Area = b h Triangle: Perimeter = a + b + c Area = (b h)/2

9 Trapezoid: Perimeter = a + b + c + d Circle: Perimeter = 2 pi r or Perimeter = pi d Area = pi r 2 or Area = (pi d 2 )/4

10 Surface area formulas Cube: Surface area = 6 a 2 Right circular cylinder: Surface area = 2 pi r pi r h pi = 3.14 h is the height r is the radius

11 Rectangular prism: Surface area = 2 l w + 2 l h + 2 w h l is the length w is the width h is the height Sphere: Surface area = 4 pi r 2 pi = 3.14 r is the radius

12 Right circular cone: Surface area = pi r 2 + pi r ( (h 2 + r 2 )) pi = 3.14 r is the radius h is the height l is the slant height Right square pyramid: Surface area = s s l s is the length of the base h is the height l is the slant height

13 The Formula for finding Interior Angles An interior angle of a regular polygon with n sides is (n 2) 180 n Example: To find the measure of an interior angle of a regular octagon, which has 8 sides, apply the formula above as follows: ( (8-2) 180) /8 = 135 Formula for sum of exterior angles: The sum of the measures of the exterior angles of a polygon, one at each vertex, is: 360. Measure of a Single Exterior Angle Formula To find 1 angle of a regular convex polygon of n sides = Formula for finding diagonals in polygons Use the formula (n² - 3n)/2. "n" represents the sides of a polygon, so if you had a pentagon and you wanted to figure out the diagonals, insert "5" for n. The result will become: 1. (5² - 3(5))/2 2. (25-15)/ /2 4. The number of diagonals for a pentagon is 5. Hexagon (6 sides) 1. (6² - 3(6))/2 2. (36-18)/ /2 4. There are 9 diagonals.

14 Decagon (10 sides) 1. (10² - 3(10))/2 2. (100-30)/ /2 4. There are 35 diagonals. Icosagon (20 sides) 1. (20² - 3(20))/2 2. (400-60)/ /2 4. There are 170 diagonals. 96-gon (the polygon Archimedes used to find the approximate value of Pi) 1. (96² - 3(96))/2 2. ( )/ /2 4. There are 4464 diagonals. Formula for finding how many total squares are in the diagram You have a 5 x 5 column your formula for finding how many total squares you can arrange from the diagram is: = = 55 total squares

15 If you have a 4 x 5 column diagram, your formula will be: 5 x 4 = 20 4 x 3 = 12 3 x 2 = 6 2 x 1 = 2 Add totals sums together: 40 total Squares you can arrange. Conversion of BASE logs Here are the formulas for converting to Base 10 and from Base 10 Converting to base 10 Problem# convert to base 10 Follow the color sequences. 3 x = 1 3 x = 5 3 x = 15 3 x = 46 3 x = 140 Answer is:

16 Now, let s convert is back to base R R R0 1 - R2 So the base 3 is: , it converts back to the original number. You must write it from the bottom up to the top remainder. Prime Factorization vs Prime Factors There is always confusion over the Prime Factorization and the Prime Factors. Let s first start with Prime Factorization, because you have to know what factors are in the number. Prime factorization breaks down the number to the lowest factors that are in it, for example: 100 = 2 x 2 x 5 x 5 - this is called Prime Factorization. Now, what are the prime numbers in the prime factorization? Answer: 2 and 5 these are the Prime Factors. Here is the break down, out of the number 100, Prime Factorization is: 2 2 x 5 2 or 2 x 2 x 5 x 5 Prime Factors are: 2 and 5

17 Formula for: Work x Time x # of Workers # of Workers 4 10 Work 9 x? Time 5 10 Or: (per hour)

18 Roman Numerals Roman numerals are expressed by letters of the alphabet: I = 1 V = 5 X = 10 L = 50 C = 100 D = 500 M = 1000 There are three basic principles for reading and writing Roman numerals: 1. A letter repeats its value that many times (XXX = 30, CC = 200, etc.). A letter can only be repeated three times. 2. If one or more letters are placed after another letter of greater value, add that amount. VI = 6 (5 + 1 = 6) LXX = 70 ( = 70) MCC = 1200 ( = 1200) 3~If a letter is placed before another letter of greater value, subtract that amount. IV = 4 (5-1 = 4) XC = 90 ( = 90) CM = 900 ( = 900)

19 Roman Numerals - Con'd Math Formulas Several rules apply for subtracting amounts from Roman numerals: a. Only subtract powers of 10( I, X, or C, but not V or L) For 95, do NOT write VC(100-5). DO write XCV (XC + V or ) b. Only subtract one number from another For 13, do NOT write IIXV (15-1-1) DO write XIII (X + I + I + I or ) c. Do not subtract a number from one that is more than 10 times greater( that is, you can subtract 1 from 10 (IX) but not 1 from 20 - there is no such number as IXX). For 99, do NOT write IC (C - I or 100-1) DO write XCIX (XC + IX or )